There is no simple answer; no two homes or businesses are the same. The size of your home or business, the number of people, their ages, each having different in/out schedules, the number of pets and their breeds, heating and cooling run times, different intake of outside air… each of these factors can reduce or multiply the air filter change frequency many times over.
The answer is “change your heating or cooling air filter when it is dirty.”
There are a couple of myths out there that should be put to bed before we continue. It has been said that household dust is comprised of mostly dead human skin cells that have been shed from our bodies. Although these skin cells are indeed in the dust in our homes, the claims that eighty plus percent are these cells is just not true. Dust contains many elements such as dust mites, animal dander, insect waste and good old fashion dirt.
All this being said, you should check your air filter at least once a month to see how dirty it is getting.
Most of the time it is pretty obvious that an air filter is in need of replacing but here are some signs to look for that can tell you it’s time to change it:
- If your air filter is damp or wet
- If the filter has been pulled into the unit by the airflow
- If you hold it up to a light and little or no light is visible through the air filter
- If the amount of air coming out of your registers and grilles has gone down significantly
- If there is a build-up of dust on your registers or grilles (air has started to bypass the filter)
Our best advice is to check the filter once a month; since your air filter has a direct impact on the performance of your heating and cooling system which has a direct effect on your power bill, a good reminder is to plan to check at the same time you pay your power bill. If it’s dirty, change it. If not, check again in a week or two. Once you do this, you’ll get a feel for how often your heating and cooling air filters should be changed.